Parametrical optical effects in the incommensurate phase of a₂bx₄crystals

Behaviour of the Optical Birefringence in Conditions of the "Viscous" Interaction

“…Their shape vIew has been discussed in different works [3,4]. Moreover, the magnitude of δ(Δn) anomalies is considerably changed depending from the investigated crystal [5][6][7] and the sample of the same crystal [8]. In accordance with Refs.…”

Birefringent and Dielectric Properties of [N(C2H5)4]2ZnBr4and [N(C2H5)4]2CdBr4Crystals

“…The critical index β in this case is equal to 0.49±0.01 (insert in Fig. 2) which corresponds to the Landau theory conceuing phase transitions of second order [5]. For c-cut of [N(C2H5)4]2CdBr4 crystals, as it would be expected, δ (Δn c ) = 0 for T > 150 K. Starting from T = 150 K, δ(Δnc ) increases.…”

Influence of cationic substitution on lattice constants and optical characterization in solution grown mixed crystals of potassium‐ ammonium zinc chloride

“…So, we believe that the structure observed in the (αhν) 1/2 plot is not due to emission and absorption of phonon. For such kinds of the alloys crucial role may play domain-like solitons [21,22]. Particular such kinds of domain walls may give to indirect phonon assisted transitions.…”